package com.gzhryc.common.secruity;

import java.security.InvalidAlgorithmParameterException;
import java.security.Key;
import java.security.spec.AlgorithmParameterSpec;

import javax.crypto.Cipher;
import javax.crypto.SecretKeyFactory;
import javax.crypto.spec.DESKeySpec;
import javax.crypto.spec.IvParameterSpec;

import com.gzhryc.common.StringTools;

/**
 * DES加密
 * @author 张浩
 * @version 2016-9-5
 */
public class DESTools {

	public static final String ALGORITHM_DES = "DES/CBC/PKCS5Padding";
	
	/**
     * DES算法，加密
     *
     * @param data 待加密字符串
     * @param key  加密私钥，长度不能够小于8位
     * @return 加密后的字节数组，一般结合Base64编码使用
     * @throws InvalidAlgorithmParameterException
     * @throws Exception
     */
    public static String encrypt(String privateKey,String key,String data) {
        if(data == null)
            return null;
        try{
            DESKeySpec dks = new DESKeySpec(key.getBytes());           
            SecretKeyFactory keyFactory = SecretKeyFactory.getInstance("DES");
            //key的长度不能够小于8位字节
            Key secretKey = keyFactory.generateSecret(dks);
            Cipher cipher = Cipher.getInstance(ALGORITHM_DES);
            IvParameterSpec iv = new IvParameterSpec(privateKey.getBytes());
            AlgorithmParameterSpec paramSpec = iv;
            cipher.init(Cipher.ENCRYPT_MODE, secretKey,paramSpec);          
            byte[] bytes = cipher.doFinal(data.getBytes());           
            return StringTools.byteArr2HexStr(bytes);
        }catch(Exception e){
            e.printStackTrace();
            return data;
        }
    }
    
    /**
     * DES算法，解密
     *
     * @param data 待解密字符串
     * @param key  解密私钥，长度不能够小于8位
     * @return 解密后的字节数组
     * @throws Exception 异常
     */
    public static String decrypt(String privateKey,String key,String data) {
        if(data == null)
            return null;
        try {
            DESKeySpec dks = new DESKeySpec(key.getBytes());
            SecretKeyFactory keyFactory = SecretKeyFactory.getInstance("DES");
            //key的长度不能够小于8位字节
            Key secretKey = keyFactory.generateSecret(dks);
            Cipher cipher = Cipher.getInstance(ALGORITHM_DES);
            IvParameterSpec iv = new IvParameterSpec(privateKey.getBytes());
            AlgorithmParameterSpec paramSpec = iv;
            cipher.init(Cipher.DECRYPT_MODE, secretKey, paramSpec);
            return new String(cipher.doFinal(StringTools.hexStr2ByteArr(data)));
        } catch (Exception e){
            e.printStackTrace();
            return data;
        }
    }
}
